Protection of polycarbonate from ultraviolet radiation

Abstract

A method is disclosed for reducing ultraviolet radiation degradation of polycarbonate by means of an ultraviolet radiation screening compound incorporated in a tetrabutyltitanate film which does not interfere with lamination of polyurethane to the polycarbonate surface.

What is claimed is: 
     
       1. A method for reducing the ultraviolet radiation degradation of polycarbonate which comprises the steps of: a. applying a solution consisting essentially of an organic ultraviolet radiation screening compound and tetrabutyltitanate onto a polycarbonate surface; and   b. curing the tetrabutyltitanate to form a hard crosslinked film.   
     
     
       2. The method according to claim 1, wherein the organic ultraviolet radiation screening compound and tetrabutyltitanate are in solution in an alcoholic solvent. 
     
     
       3. The method according to claim 2, wherein the solvent comprises isopropanol. 
     
     
       4. The method according to claim 3, wherein the organic ultraviolet radiation screening compound is selected from the group consisting of o-hydroxybenzophenone, phenyl salicylate, substituted benzotriazoles and mixtures thereof. 
     
     
       5. The method according to claim 4, wherein the ratio of organic ultraviolet radiation screening compound to tetrabutyltitanate is from 1:1 to 4:1. 
     
     
       6. An article comprising a polycarbonate substrate, on at least one major surface of which is a film consisting essentially of tetrabutyltitanate containing an organic ultraviolet radiation screening compound. 
     
     
       7. The article of claim 6, wherein the organic ultraviolet radiation screening compound is selected from the group consisting of o-hydroxybenzophenone, phenyl salicylate, substituted benzotriazoles and mixtures thereof. 
     
     
       8. In a method of laminating polyurethane to polycarbonate, the improvement which comprises applying to the polycarbonate surface a film forming composition comprising tetrabutyltitanate and an organic ultraviolet radiation screening compound and curing the tetrabutyltitanate prior to bonding the polyurethane and polycarbonate surfaces. 
     
     
       9. A laminated article which comprises: a. at least one ply of polycarbonate;   b. at least one ply of polyurethane bonded to said polycarbonate ply; and   c. a tetrabutyltitanate film comprising an organic ultraviolet radiation screening compound at the interface of said polyurethane and polycarbonate plies.   
     
     
       10. An article according to claim 9, wherein said organic ultraviolet radiation screening compound is selected from the group consisting of o-hydroxybenzophenone, phenyl salicylate, substituted benzotriazoles and mixtures thereof.